Claims:

2. The halo-functional silane of claim 1 selected from one of general
Formulae (1) and (2):Y1(--Siz.sup.θX1)a
(1),and[Y1(--SiZ.sup.θZ.sup.β)a]m[Y1(--SiZ-
.sup.β3)a]n[Y1(--SiZ.sup.β2X1).sub-
.a]o[[Y1(--SiZ.sup.βX.sup.1.sub.2)a]p
(2)wherein:each occurrence of Y1 is a monovalent or polyvalent
halo-containing hydrocarbon group of up to 30 carbon atoms of general
Formula (3)[(ZeCR3-e)bY2]cG.sup.1.sub.d
(3)wherein each occurrence of G1 is independently a divalent or
polyvalent hydrocarbon group up to 18 carbon atoms that can optionally
contain at least one heteroatom selected from the group consisting of
oxygen, sulfur, phosphorous and silicon; each occurrence of Y2 is
independently an unsaturated group; each occurrence of Z is independently
a halogen atom selected from the groups consisting of F--, Cl--, Br-- and
I--; and, each occurrence of R is independently selected from the group
consisting of hydrogen, alkyl, alkenyl, aryl or aralkyl wherein each R,
other than hydrogen, contains up to 30 carbon atoms;each occurrence of
X1 is independently selected from the group consisting of hydrogen,
alkyl groups and hydrolyzable groups;each occurrence of Z.sup.β,
which forms a bridging structure between two different silicon atoms, is
[--OG2(OH)f-2O--].sub.0.5, wherein each occurrence of G2
is independently selected form the group consisting of a hydrocarbylene
group of from 2 to 15 carbon atoms or a divalent heterocarbylene group of
from 4 to 15 carbon atoms containing one or more etheric oxygen
atoms;each occurrence of Z.sup.θ, which forms a cyclic structure
with a silicon atom, is --OG2(OH)f-2O--, wherein G2 is
independently selected form the group consisting of a hydrocarbylene
group of from 2 to 15 carbon atoms or a divalent heterocarbylene group of
from 4 to 15 carbon atoms containing one or more etheric oxygen atoms;
and,each occurrence of subscripts a, b, c, d, e, f, m, n, o and p is
independently an integer where a is 1 to 5; b is 1 to 5; c is 1 to 3,
with the proviso that when d is zero, c is 1 and when d is 1, c is from 1
to 3; d is 0 or 1; e is 1 to 3; f is 2 to 6; m is 0 to 20; n is 0 to 18;
o is 0 to 20; and, p is 0 to 20, with the proviso that m+n+o+p is equal
to or greater than 2.

3. The halo-functional silane of claim 2 wherein each X1 is
independently an alkoxy group.

7. The halo-functional silane of claim 2 wherein each G1
independently is selected from the group consisting of diethylene
cyclohexane; 1,2,4-triethylene cyclohexane; diethylene benzene;
phenylene; --(CH2)j-- wherein j is up to 18; any of the
structures derivable from divinylbenzene; any of the structures derivable
from dipropenylbenzene; any of the structures derivable from butadiene;
any of the structures derivable from piperylene; any of the structures
derivable from isoprene; any of the isomers of
--CH2CH2-norbornyl-, --CH2CH2-cyclohexyl-; any of the
diradicals obtainable from norbornane, cyclohexane, cyclopentane,
tetrahydrodicyclopentadiene or cyclododecene by loss of two hydrogen
atoms; any of the structures derivable from limonene,
--CH2CH(4-CH3-1-C6H9--)CH3, where the notation
C6H9 denotes isomers of the trisubstituted cyclohexane ring
lacking substitution in the 2 position; any of the monovinyl-containing
structures derivable from trivinylcyclohexane; any of the monounsaturated
structures derivable from myrcene containing a trisubstituted
--C═C--; any of the monounsaturated structures derivable from myrcene
lacking a trisubstituted --C═C--; any of the straight chain or
branched alkylenes substituted with at least one heteroatom.

8. The halo-functional silane of claim 2 wherein Y2 is a divalent or
polyvalent unsaturated hydrocarbon group of up to 12 carbon atoms
containing at least one carbon-carbon double bond that is bonded to the
--CR3-eZe fragment or at least one carbon-carbon triple bond
that is bonded to the --CR3-eZe fragment.

9. The halo-functional silane of claim 2 wherein Z is Cl--.

10. The halo-functional silane of claim 2 wherein each R independently is
hydrogen or a straight, branched or cyclic alkyl group of up to 30 carbon
atoms, or a straight, branched or cyclic alkenyl group of up to 30 carbon
atoms containing one or more carbon-carbon double bonds where the point
of substitution can be either at a carbon-carbon double bond or elsewhere
in the group.

11. The halo-functional silane of claim 2 wherein each R independently is
hydrogen or a straight, branched or cyclic alkyl group of up to 6 carbon
atoms, or a straight, branched or cyclic alkenyl group of up to 6 carbon
atoms containing one or more carbon-carbon double bonds where the point
of substitution can be either at a carbon-carbon double bond or elsewhere
in the group.

12. The halo-functional silane of claim 2 wherein each R independently is
hydrogen or a straight, branched or cyclic alkyl group of up to 3 carbon
atoms, or a straight, branched or cyclic alkenyl group of up to 3 carbon
atoms containing one or more carbon-carbon double bonds where the point
of substitution can be either at a carbon-carbon double bond or elsewhere
in the group.

13. The halo-functional silane of claim 2 wherein the
[--Y--(CR3-e--Ze)b] moiety of silane of general Formula
(3) is selected from the group consisting of --CH═CH--CH2--Cl,
--CH═CH--CH(CH3)--Cl, --CH═C(CH3)--CH2--Cl
--C≡CCH2--Cl and --C6H4--CH2--Cl where
C6H4 represents an divalent substituted benzene ring,
--C6H4--CH(CH3)--Cl, --C6H4CH2--Br,
--C6H4CHCl2, and --C6H4CCl.sub.3.

14. The halo-functional silane of claim 2 wherein each a, b, c and d
independently is an integer in which a is 1; b is 1 or 2; c is 1 or 2; d
is 0 or 1; and e is 1 or 2.

15. The halo-functional silane of claim 14 wherein a is 1; b is 1; c is 1;
d is 1; and, e is 1.

18. The halo-functional silane of claim 1 obtained by the process which
comprises reacting a halo-functional silane derived from mono-alcohol
with at least one polyhydroxyl-containing compound and removing
by-product mono-alcohol.

19. A process for preparing the halo-functional silane of claim 1 which
comprises reacting a halo-functional silane derived from mono-alcohol
with at least one polyhydroxyl-containing compound and removing
by-product mono-alcohol.

20. A process for preparing the halo-functional silane of Formula (1)
and/or (2) of claim 2 which comprises reacting:a) at least one
halo-functional silane selected from the group consisting of general
Formula (4):[X2X3X4Si--]a(G1)d[--Y2--(-
CR3-eZe)b]c (4)wherein:each occurrence of X2 is
independently selected from a hydrolyzable group consisting of Cl--,
Br--, I--, R1O--, R1(═O)O--, R.sup.1.sub.2C═NO-- and
R.sup.1.sub.2NO-- wherein each R1 is independently selected from the
group consisting of hydrogen, alkyl, alkenyl, aryl and aralkyl groups,
with each R1, other than hydrogen, containing up to 18 carbon atoms
and, optionally, one or more heteroatoms selected from the group
consisting of oxygen and sulfur;each occurrence of X3 and X4 is
independently selected from X2 and R2 groups wherein each
R2 is independently selected from the group consisting of hydrogen,
straight, cyclic or branched alkyl, alkenyl, aryl and aralkyl groups,
with each R2, other than hydrogen, containing up to 18 carbon atoms
and, optionally, one or more heteroatoms selected from the group
consisting of oxygen and sulfur;each occurrence of G1 is
independently a divalent or polyvalent hydrocarbon group of up to 18
carbon atoms optionally containing one or more heteroatoms selected from
the group consisting of oxygen, sulfur, phosphorous and silicon;each
occurrence of Y2 is independently an unsaturated group;each
occurrence of Z is independently a halogen atom selected from the group
consisting of F--, Cl--, Br-- and I--;each occurrence of R is
independently selected from the group consisting of hydrogen, alkyl,
alkenyl, aryl or aralkyl, with each R, other than hydrogen, containing up
to 30 carbon atoms; and,each occurrence of subscripts a, b, c and d is
independently an integer where a is 1 or 5; b is 1 to 5; c is 1 to 3,
with the provisos that when d is zero, c is 1 and when d is 1, c is from
1 to 3; d is 0 or 1; and, e 1 to 3; withb) one or more
polyhydroxyl-containing compounds of general Formula
(5):G2(OH)f (5)wherein G2 is a hydrocarbyl group of from
2 to 15 carbon atoms or a heterocarbyl group of from 4 to 15 carbon atoms
containing one or more etheric oxygen atoms and f is an integer of from 2
to 6, under transesterification reaction conditions, and accompanied by
removal of by-product mono-alcohol, thereby producing halo-functional
silane.

21. The process of claim 25 wherein at least one of X2, X3 and
X4, each occurrence, is independently the group R1O.

23. The process of claim 20 wherein polyhydroxyl-containing compound of
Formula (5) is a diol of at least one of the general Formulae (6) and
(7):HO(R0CR0)gOH
(6)HO(CR.sup.0.sub.2CR.sup.0.sub.2O)hH (7)wherein R0 is
independently given by one of the members for R as previously defined, g
is 2 to 15 and h is 2 to 7.

24. The process of claim 23 wherein the polyhydroxyl-containing compound
of Formula (5) is at least one diol selected from the group consisting of
HOCH2CH2OH, HOCH2CH2CH2OH,
HOCH2CH2CH2CH2OH, HOCH2CH(CH3)CH2OH,
(CH3)2C(OH)CH2CH(OH)CH3,
CH3CH(OH)CH2CH2OH, HOCH2CH2OCH2CH2OH,
HOCH2CH2CH2OCH2CH2CH2OH,
HOCH2CH(CH3)OCH2CH(CH3)OH and polyether diol and/or
at least one higher functionality polyhydroxyl-containing compound
selected from the group consisting of glycerol, trimethylolethane,
trimethylolpropane, 1,2,4-butanetriol, 1,2,6-hexanetriol,
pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol,
galacticol and sorbitol.

32. The composition of claim 31, wherein the silane-reactive filler (a) is
at least one selected from the group consisting of silica, titanium
dioxide, aluminosilicate, alumina and siliceous materials, and
combinations thereof

33. The rubber composition of claim 25, wherein the silane (c) is
pre-mixed or pre-reacted with the silane-reactive filler (b).

34. The rubber composition of claim 33, wherein the silane-reactive filler
(b) is at least one selected from the group consisting of silica,
titanium dioxide, aluminosilicate, alumina and siliceous materials, and
combinations thereof.

Description:

BACKGROUND OF THE INVENTION

[0001]This invention relates to halo-functional silanes, their
preparation, rubber compositions containing same and articles such as
tires manufactured therefrom.

[0002]The use of the silica/silane-filler system to reduce the rolling
resistance and improve the wet traction of passenger car tires is well
known in the art. A reduction of rolling resistance, and therefore less
fuel consumption, is also of strong interest for truck tires. However,
the use of silica to replace carbon black filler in natural rubber (NR)
containing formulations such as truck tread compounds is limited due to
poor abrasion resistance. At the present time, truck tire treads use
highly reinforcing carbon black for maximum reinforcement and excellent
resistance to abrasion. The replacement of carbon black by silica in
truck applications has been hampered by ineffective coupling of the
silica to the polymer chains of natural rubber.

[0003]Polysulfurized alkoxysilanes such as
bis(triethoxysilylpropyl)tetrasulfide (TESPT) and blocked
mercapto-functional silanes such as
3-octanoylthio-1-propyltriethoxysilane are currently regarded as the most
effective and the most widely used coupling agents in rubber compositions
for tires, especially those compositions containing styrene-butadiene
rubber or butadiene rubber. The reinforcing efficiency and abrasion
resistance of vulcanizates filled with silica are not good enough to
justify the replacement of carbon black in formulations containing high
levels of natural rubber.

[0004]The use of non-sulfur silanes is focused on the use of activated
double bonds to improve the coupling between fillers and polymer, notably
natural rubber. But these non-sulfur coupling agents have shown
inadequate coupling performance or performance inferior to that offered
by polysulfurized silanes such as bis(triethoxysilylpropyl)tetrasulfide.
In addition, the known non-sulfur silanes are very reactive with
conventional fillers and elastomers and are therefore difficult to use.
When known non-sulfur silanes are used at levels necessary to achieve
optimum coupling of filler to the host elastomer, the uncured filled
elastomer typically exhibits poorly dispersed filler and short scorch
times during curing. Both good filler dispersion and good filler
reinforcing efficiency are required to achieve satisfactory end-use
properties.

[0005]Commonly assigned, copending U.S. patent application Ser. No.
11/703,969, filed Feb. 8, 2007, addresses the inadequate coupling
performance of non-sulfur silanes by using halo-functional silane. This
halo-functional silane is derived from mono-alcohols that generate
volatile organic compound (VOC's) emissions during their use in filled
elastomers. The mono-alcohols that are formed during use of the
halo-functional silane have low flash points and therefore create
potential hazards during fabrication and use. In addition, the
mono-alcohol derived halo-functional silanes generate mono-alcohols
during use that may impact adversely on the environment.

[0007]It would be desirable for various rubber applications to have a
rubber composition that utilizes increased levels of silica and lower
levels of carbon black while maintaining low VOC emissions from the
filled elastomeric materials and elastomeric articles during their
preparation and use and still exhibiting the properties of low scorch,
good filler dispersion and improved abrasion resistance.

SUMMARY OF THE INVENTION

[0008]In accordance with the present invention, there is provided a
halo-functional silane containing at least one alkanedioxysilyl group.

[0009]Further in accordance with the invention, there is provided a
process for preparing the aforesaid halo-functional silane which
comprises reacting a halo-functional silane derived from mono-alcohol
with at least one polyhydroxyl-containing compound and removing
by-product mono-alcohol.

[0010]Still further in accordance with the invention, there is provided a
rubber composition comprising: [0011](a) at least one rubber component;
[0012](b) at least one silane-reactive filler; [0013](c) at least one
halo-functional silane containing alkanedioxysilyl group; and, [0014](d)
optionally, at least one activating agent.

[0015]The "halo-functional silane" of the present invention is a
monomeric, dimeric, oligomeric or polymeric compound possessing halogen
functionality and alkanedioxysilyl functionality derived from
polyhydroxyl-containing compounds in which the alkanedioxy group is
covalently bonded to a single silicon atom through silicon-oxygen bonds
to form a ring and/or the alkanedioxy group is covalently bonded to at
least two silicon atoms through silicon-oxygen bond to form dimer,
oligomer or polymer in which adjacent silyl units are bonded to each
other through bridged alkanedialkoxy structure. It is understood that
alkanedioxysilyl functionality may contain more than two silicon-oxygen
bonds and/or hydroxyl groups that are bonded to the alkanedioxysilyl
group through carbon-oxygen bonds.

[0016]Other than in the working examples or where otherwise indicated, all
numbers expressing amounts of materials, reaction conditions, time
durations, quantified properties of materials, and so forth, stated in
the specification and claims are to be understood as being modified in
all instances by the term "about."

[0017]It will also be understood that any numerical range recited herein
is intended to include all sub-ranges within that range and any
combination of the various endpoints of such ranges or subranges.

[0018]It will be further understood that any compound, material or
substance which is expressly or implicitly disclosed in the specification
and/or recited in a claim as belonging to a group of structurally,
compositionally and/or functionally related compounds, materials or
substances includes individual representatives of the group and all
combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION

[0019]As previously stated, the halo-functional silane containing at least
one alkanedioxysilyl group of this invention provides unique coupling
interactions between silane-reactive filler and rubber component and
reduces or eliminates the generation of volatile organic compounds.

[0020]In accordance with the following embodiments of the halo-functional
silane of the invention, the silane may be selected from one or more of
general Formulae (1) and/or (2):

[0021]each occurrence of Y1 is a monovalent or polyvalent
halo-containing hydrocarbon group of up to 30 carbon atoms of general
Formula (3)

[(ZeCR3-e)bY2]cG1d (3)

wherein each occurrence of G1 is independently a divalent or
polyvalent hydrocarbon group of up to 18 carbon atoms that can optionally
contain at least one heteroatom selected from the group consisting of
oxygen, sulfur, phosphorous and silicon; each occurrence of Y2 is
independently an unsaturated group; each occurrence of Z is independently
a halogen atom selected from the groups consisting of F--, Cl--, Br-- and
I--; and, each occurrence of R is independently selected from the group
consisting of hydrogen, alkyl, alkenyl, aryl or aralkyl wherein each R,
other than hydrogen, contains up to 30 carbon atoms;

[0022]each occurrence of X1 is independently selected from the group
consisting of hydrogen, alkyl groups and hydrolyzable groups; each
occurrence of Z.sup.β, which forms a bridging structure between two
different silicon atoms, is [--OG2(OH)f-2O--]0.5, wherein
each occurrence of G2 is independently selected form the group
consisting of a hydrocarbylene group of from 2 to 15 carbon atoms or a
divalent heterocarbylene group of from 4 to 15 carbon atoms containing
one or more etheric oxygen atoms;

[0023]each occurrence of Z.sup.θ, which forms a cyclic structure
with a silicon atom, is --OG2(OH)f-2O--, wherein G2 is
independently selected form the group consisting of a hydrocarbylene
group of from 2 to 15 carbon atoms or a divalent heterocarbylene group of
from 4 to 15 carbon atoms containing one or more etheric oxygen atoms;
and,

[0024]each occurrence of subscripts a, b, c, d, e, f, m, n, o and p is
independently an integer where a is 1 to 5; b is 1 to 5; c is 1 to 3,
with the proviso that when d is zero, c is 1 and when d is 1, c is from 1
to 3; d is 0 or 1; e is 1 to 3; f is 2 to 6; m is 0 to 20; n is 0 to 18;
o is 0 to 20; and, p is 0 to 20, with the proviso that m+n+o+p is equal
to or greater than 2.

[0025]In connection with the silanes of Formulae (1) and (2), the term
"alkyl" includes straight, branched and cyclic alkyl groups; the term
"alkenyl" includes any straight, branched, or cyclic alkenyl group
containing one or more carbon-carbon double bonds, where the point of
substitution can be either at a carbon-carbon double bond or elsewhere in
the group; the term "alkynyl" includes any straight, branched or cyclic
alkynyl group containing one or more carbon-carbon triple bonds, where
the point of substitution can be either at a carbon-carbon triple bond or
elsewhere in the group; the term "aryl" includes the non-limiting group
of any aromatic hydrocarbon from which one hydrogen atom has been
removed; the term "aralkyl" includes, but is not limited to, any of the
aforementioned alkyl groups in which one or more hydrogen atoms have been
substituted by the same number of like and/or different aryl (as defined
herein) substituents. Specific examples of alkyl groups include, but are
not limited to, methyl, ethyl, propyl and isobutyl. Specific examples of
alkenyl groups include, but are not limited to, vinyl, propenyl, allyl,
methallyl, ethylidenyl norbornane, ethylidene norbornyl and ethylidene
norornenyl. Specific examples of aryl groups include, but are not limited
to, tolyl, xylyl, phenyl and naphthalenyl. Specific examples of aralkyl
groups include, but are not limited to, benzyl and phenethyl.

[0026]In connection with the silanes Formulae (1) and (2), group X1
is selected from the group consisting of hydrogen, alkyl groups and
hydrolyzable groups. Some non-limiting representative examples of X1
include methyl, ethyl, propyl, isopropyl, sec-butyl and cyclohexyl;
higher straight-chain alkyl such as butyl, hexyl, octyl, lauryl and
octadecyl; alkenyl groups such as the non-limiting examples vinyl, allyl,
methallyl and 3-butenyl; aryl groups such as the non-limiting examples
phenyl and tolyl; aralkyl groups such as the non-limiting examples benzyl
and phenethyl; alkoxy groups such as the non-limited examples methoxy,
ethoxy, propoxy, isopropoxy, butoxy, phenoxy and benzyloxy; hydroxyl
group; halo groups such as the non-limiting examples chloro, bromo and
iodo; oximato groups such as the non-limiting examples
methylethyloximato, phenylmethyloximato and dimethyloximato; amineoxy
groups such as the non-limiting dimethylamineoxy, diethylamineoxy and
methylethylamineoxy.

[0027]In connection with the structural fragment of Formula (3), group
G1 can be any divalent or polyvalent hydrocarbon and can optionally
contain at least one heteroatom selected from the group consisting of
oxygen, sulfur, phosphorus and silicon atoms. Group G1 can contain
up to 18, preferably up to 12, more preferably up to 8 and most
preferably up to 4, carbon atoms.

[0028]Representative examples of group G1 include, but are not
limited to, diethylene cyclohexane; 1,2,4-triethylene cyclohexane;
diethylene benzene; phenylene; --(CH2)j-- wherein j is an
integer of from 1 to 18, which represent terminal straight-chain alkyls,
such as --CH2--, --CH2CH2--, --CH2CH2CH2--
and --CH2CH2CH2CH2CH2CH2CH2CH2--,
and their beta-substituted analogs such as
--CH2(CH2)iCH(CH3)-- wherein i is an integer of from
preferably 0 to 15; --CH2CH2C(CH3)2CH2--; the
structure derivable from methallyl chloride,
--CH2CH(CH3)CH2--; any of the structures derivable from
divinylbenzene such as
--CH2CH2(C6H4)CH2CH2-- and
--CH2CH2(C6H4)CH(CH3)-- where the notation
C6H4 denotes a disubstituted benzene ring; any of the
structures derivable from dipropenylbenzene such as
--CH2CH(CH3)(C6H4)CH(CH3)CH2-- where the
notation C6H4 denotes a disubstituted benzene ring; any of the
structures derivable from butadiene such as
--CH2CH2CH2CH2--, --CH2CH2CH(CH3)--
and --CH2CH(CH2CH3)--; any of the structures derivable
from piperylene such as --CH2CH2CH2CH(CH3)--,
--CH2CH2CH(CH2CH3)-- and
--CH2CH(CH2CH2CH3)--; any of the structures derivable
from isoprene such as --CH2CH(CH3)CH2CH2--,
--CH2CH(CH3)CH(CH3)--,
--CH2C(CH3)(CH2CH3)--,
--CH2CH2CH(CH3)CH2--,
--CH2CH2C(CH3)2-- and
--CH2CH[CH(CH3)2]--; any of the isomers of
--CH2CH2-norbornyl-, --CH2CH2-cyclohexyl-; any of the
diradicals obtainable from norbornane, cyclohexane, cyclopentane,
tetrahydrodicyclopentadiene or cyclododecene by loss of two hydrogen
atoms; the structures derivable from limonene,
--CH2CH(4-CH3-1-C6H9--)CH3, where the notation
C6H9 denotes isomers of the trisubstituted cyclohexane ring
lacking substitution in the 2 position; any of the monovinyl-containing
structures derivable from trivinylcyclohexane such as
--CH2CH2(vinylC6H9)CH2CH2-- and
--CH2CH2(vinylC6H9)CH(CH3)-- where the notation
C6H9 denotes any isomer of the trisubstituted cyclohexane ring;
any of the monounsaturated structures derivable from myrcene containing a
trisubstituted --C═C-- such as
--CH2CH[CH2CH2CH═C(CH3)2]CH2CH2--,
CH2CH[CH2CH2CH═C(CH3)2]CH(CH3)--,
--CH2C[CH2CH2CH═C(CH3)2](CH2CH3)---
, --CH2CH2CH[CH2CH2CH═C(CH3)2]CH2---
, --CH2CH2(C--)(CH3)[CH2CH2CH═C(CH3).sub-
.2] and --CH2CH[CH(CH3)(CH2CH2CH═C(CH3)2-
)]--; any of the monounsaturated structures derivable from myrcene lacking
a trisubstituted --C═C-- such as
--CH2CH(CH═CH2)CH2CH2CH2C(CH3)2--,
--CH2CH(CH═CH2)CH2CH2CH[CH(CH3)2]--,
--CH2C(═CH--CH3)CH2CH2CH2C(CH3)2---
, --CH2C(═CH--CH3)CH2CH2CH[CH(CH3)2]--,
--CH2CH2C(═CH2)CH2CH2CH2C(CH3).sub-
.2--, --CH2CH2C(═CH2)CH2CH2CH[CH(CH3).su-
b.2]--, --CH2CH═C(CH3)2CH2CH2CH2C(CH.sub-
.3)2-- and
--CH2CH═C(CH3)2CH2CH2CH[CH(CH3)2]--
-; and, any of the straight chain or branched alkylenes substituted with
at least one heteroatom such as --CH2CH2OCH2--,
--CH2CH2OCH2CH2OCH2CH2--,
--CH2CH2SCH2CH2SCH2CH2--,
--CH2CH2Si(CH3)2CH2CH2--.

[0029]In connection with the structural fragment of Formula (3), group
Y2 therein is a divalent or polyvalent unsaturated hydrocarbon group
of from 2 to 12 carbon atoms containing at least one carbon-carbon double
bond or at least one carbon-carbon triple bond that of Formula (3). The
carbon-carbon double bond or carbon-carbon triple bond can be conjugated
or non-conjugated with other carbon-carbon double and/or triple bonds and
can include aromatic ring structures. When b in Formula (3) is at least
2, the --CR3-eZe fragments can be bonded to the same carbon
atom on the carbon-carbon double bond, on adjacent carbon atoms of the
carbon-carbon double bond or on the carbon atoms of different
carbon-carbon bonds. Some non-limiting representative examples of Y2
are alkenylene groups such as --CH═CH--, --CH2CH═CH--,
--CH2CH2CH═CH-- and --CH2CH═CH--CH═CH-- and
--CH═C(-)2; alkynylene groups such as --C≡C--,
--CH2C≡C-- and --CH2CH2C≡C--; and, aromatic
groups such as phenylene and 2-methylphenylene.

[0031]In structural fragment Formula (3), R is hydrogen; a straight,
branched or cyclic alkyl group of up to 30, preferably up to 10, more
preferably up to 6, and most preferably up to 3, carbon atoms; a
straight, branched or cyclic alkenyl group containing one or more
carbon-carbon double bond where the point of substitution can be either
at a carbon-carbon double bond or elsewhere in the group and where the
alkenyl group contains up to 30, more preferably up to 10, more
preferably up to 6, and most preferably up to 3, carbon atoms; and, an
aryl group containing up to 30, more preferably up to 20, more preferably
up to 12, and most preferably up to 8, carbon atoms.

[0034]In the silanes of Formulae (1) and (2), each occurrence of X1
is R1O-- wherein R1 is independently hydrogen, an alkyl group
of up to 6, more preferably of up to 3, and more preferably 2, carbon
atoms, or R2 which is independently selected from the group
consisting of hydrogen and an alkyl group of up to 6, more preferably 1
or 2, and most preferably 1, carbon atom; G1 is independently a
hydrocarbon of up to 10, more preferably up to 3, and most preferably 1,
carbon atom; each occurrence of R is independently an alkyl group of up
to 10 carbons, preferably up to 3, and most preferably 1, carbon atom;
each occurrence of Y2 is independently an unsaturated group
preferably selected from --CH═CH--, --C≡C-- and
--C6H4--, more preferably selected from --CH═CH-- and
--C6H4-- and most preferably --C6H4--; each
occurrence of Z is Cl-- or Br-- and preferably is Cl--; and, a, b, c and
d are integers in which a is 1; b is 1 or 2; c is 1 or 2; d is 0 or 1;
and e is 1 or 2, and preferably a is 1; b is 1; c is 1; d is 1; and e is
1.

[0037]The halo-functional silane of the present invention includes its
partial hydrolyzates. These partial hydrolyzates result when the
halo-function silane reacts with water to generate silanols which
thereafter condense to form siloxane bonds. The silane hydrolyzates
contain at least one Z.sup.β group which forms a bridging structure
between two different silicon atoms or at least one Z.sup.θ group
which forms a cyclic structure with a silicon atom.

[0038]The halo-functional silanes of the invention can be prepared by the
process which comprises reacting a halo-functional silane derived from
mono-alcohol with at least one polyhydroxyl-containing compound and
removing by-product mono-alcohol.

[0039]In the case of the halo-functional silanes of Formulae (1) and (2),
the foregoing process comprises reacting:

[0040]a) at least one halo-functional silane selected from the group
consisting of general Formula (4):

[X2X3X4Si--]a(G)d[--Y2--(CR3-e--Ze-
)b]c (4)

[0041]wherein:

[0042]each occurrence of X2 is independently selected from a
hydrolyzable group consisting of Cl--, Br--, I--, R1O--,
R1(═O)O--, R12C═NO-- and R12NO-- wherein
each R1 is independently selected from the group consisting of
hydrogen, alkyl, alkenyl, aryl and aralkyl groups, with each R1,
other than hydrogen, containing up to 18 carbon atoms and, optionally,
one or more heteroatoms selected from the group consisting of oxygen and
sulfur;

[0043]each occurrence of X3 and X4 is independently selected
from X2 and R2 groups wherein each R2 is independently
selected from the group consisting of hydrogen, straight, cyclic or
branched alkyl, alkenyl, aryl and aralkyl groups, with each R2,
other than hydrogen, containing up to 18 carbon atoms and, optionally,
one or more heteroatoms selected from the group consisting of oxygen and
sulfur;

[0044]each occurrence of G1 is independently a divalent or polyvalent
hydrocarbon group of up to 18 carbon atoms optionally containing one or
more heteroatoms selected from the group consisting of oxygen, sulfur,
phosphorous and silicon;

[0045]each occurrence of Y2 is independently an unsaturated group;

[0046]each occurrence of Z is independently a halogen atom selected from
the group consisting of F--, Cl--, Br-- and I--;

[0047]each occurrence of R is independently selected from the group
consisting of hydrogen, alkyl, alkenyl, aryl or aralkyl, with each R,
other than hydrogen, containing up to 30 carbon atoms; and,

[0048]each occurrence of subscripts a, b, c and d is independently an
integer where a is 1 or 5; b is 1 to 5; c is 1 to 3, with the provisos
that when d is zero, c is 1 and when d is 1, c is from 1 to 3; d is 0 or
1; and, e is 1 to 3; with

[0049]b) one or more polyhydroxyl-containing compounds of general Formula
(5):

G2(OH)f (5)

wherein G2 is a hydrocarbyl group of from 2 to 15 carbon atoms or a
heterocarbyl group of from 4 to 15 carbon atoms containing one or more
etheric oxygen atoms and f is an integer of from 2 to 6, under
transesterification reaction conditions, and accompanied by removal of
by-product mono-alcohol, thereby producing halo-functional silane.

[0050]X2 of general Formula (4) is a hydrolyzable group. Some
representative non-limiting examples of X2 include alkoxy groups
such as ethoxy, ethoxy, propoxy, isopropoxy, butoxy, phenoxy and
benzyloxy; hydroxyl group; halo groups such as chloro, bromo and iodo;
oximato groups such as methylethyloximato, phenylmethyloximato and
dimethyloximato; amineoxy groups such as dimethylamineoxy,
diethylamineoxy and methylphenyamineoxy; and, acyloxy groups such as
formyloxy, acetoxy and propanoyloxy.

[0051]Some representative non-limiting examples of X3 and X4 in
Formula (4) include the examples listed above for X2 as well as
hydrogen, alkyl groups such as methyl, ethyl, propyl, isopropyl,
sec-butyl and cyclohexyl; higher straight-chain alkyl such as butyl,
hexyl, octyl, lauryl and octadecyl; alkenyl groups such as vinyl, allyl,
methallyl and 3-butenyl; aryl groups such as phenyl and tolyl; and,
aralkyl groups such as benzyl and phenethyl

[0120]When the silane is a dimer, oligomer, or polymer, each silyl unit
thereof is bonded to an adjacent silyl unit through a bridging group
resulting from the reaction of the selected silane monomer(s) with one or
more polyhydroxyl-containing compounds of aforedescribed general Formula
(5).

[0121]In one embodiment herein, the selected polyhydrolyx-containing
compound of Formula (5) is a diol (glycol) of at least one of the general
Formulae (6) and (7):

HO(R0CR0)gOH (6)

HO(CRO2CRO2O)hH (7)

wherein R0 is independently given by one of the members listed above
for R, g is 2 to 15 and h is 2 to 7.

[0122]Some representative non-limiting examples of such diols are
HOCH2CH2OH, HOCH2CH2CH2OH,
HOCH2CH2CH2CH2OH, HOCH2CH(CH3)CH2OH,
(CH3)2C(OH)CH2CH(OH)CH3,
CH3CH(OH)CH2CH2OH, diols possessing an etheric
oxygen-containing group such as HOCH2CH2OCH2CH2OH,
HOCH2CH2CH2OCH2CH2CH2OH,
HOCH2CH(CH3)OCH2CH(CH3)OH, diols possessing a
polyether backbone such
HOCH2CH2OCH2CH2OCH2CH2OH, and diols of
Formula (6) wherein R0 is hydrogen or methyl and e is 3 or 4.

[0124]In accordance with the invention, there is provided a rubber
composition comprising: [0125](a) at least one rubber component;
[0126](b) at least one silane-reactive filler; [0127](c) at least one
halo-functional silanecontaining at least one alkanedioxysilyl group;
and, [0128](d) optionally, at least one activating agent.

[0129]Halo-functional silane component (c) in the foregoing rubber
composition is advantageously one or more of Formulae (1) and/or (2).

[0130]The rubber composition herein can optionally contain one or more
other hydrolyzable organosilanes that hydrophobate and aid in the
dispersion of silane-reactive filler (b). These hydrolyzable
organosilanes contain at least one alkyl group, preferably up to 18, and
more preferably up to 10, carbon atoms, and at least one R3O--
hydrolyzable group wherein R3 is hydrogen or an alkyl, alkenyl, aryl
or aralkyl of up to 10 carbon atoms. These hydrolyzable organosilanes can
be used, e.g., in amounts of from 0.5 to 10, and preferably from 1 to 5,
phr.

[0132]In a further embodiment of the rubber composition herein,
halo-functional silane (c) bonds to silane-reactive filler (b) through
one functionality and to rubber component (a), e.g., a diene polymer,
through a different functionality.

[0134]Rubber component (a) can be one or more diene-based elastomers
and/or rubbers and can be selected from any of those that are well known
in the art many of which are described in "The Vanderbilt Rubber
Handbook", R. F. Ohm, ed.; R.T. Vanderbilt Company, Inc., Norwalk, Conn.,
1990 and "Manual For The Rubber Industry", T. Kempermann, S. Koch, J.
Sumner, eds.; Bayer AG, Leverkusen, Germany, 1993.

[0136]Suitable monomers for preparing rubber component (a) include
conjugated dienes such as isoprene and 1,3-butadiene, and vinyl aromatic
compounds such as styrene and alpha methyl styrene, and combinations
thereof. In a particular embodiment, rubber component (a) is a
sulfur-curable rubber.

[0140]In yet another embodiment of the rubber composition of the
invention, rubber component (a) is a diene polymer functionalized or
modified by an alkoxysilane derivative. Accordingly,
silane-functionalized organic solution polymerization-prepared
styrene-butadiene rubber and silane-functionalized organic solution
polymerization-prepared 1,4-polybutadiene rubbers can be used. These
rubber compositions are known, e.g., from U.S. Pat. No. 5,821,290, the
entire contents of which are incorporated by reference herein.

[0141]In still another embodiment of the rubber composition of the
invention, rubber component (a) is a diene polymer functionalized or
modified by a tin derivative. Tin-coupled copolymers of styrene and
butadiene can be prepared, for example, by introducing a tin coupling
agent during the styrene and 1,3-butadiene monomer copolymerization
reaction in an organic solvent solution, usually at or near the end of
the reaction. Such tin-coupled styrene-butadiene rubbers are well known
in the art, e.g., from U.S. Pat. No. 5,268,439, the entire contents of
which are incorporated by reference herein. In practice, at least 50
percent, and preferably from 60 to 85 percent, of the tin is bonded to
the butadiene units of the styrene-butadiene rubbers to create a
tin-dienyl bond.

[0142]Silane-reactive filler (b) is a substance that is capable of
reaction with silane (c) to form stable Si--O-filler bonds.
Silane-reactive filler (b) includes a substance that is added to rubber
component (a) to reinforce the cured rubber composition. Reinforcing
fillers are materials whose moduli are higher than rubber component (a)
of the rubber composition and are capable of absorbing stress from rubber
component (a) when this component is strained. Suitable silane-reactive
fillers (b) includes fibers, particulates and sheet-like structures and
can be made up of inorganic minerals, silicates, silica, clays, ceramics,
carbon, organic polymers and diatomaceous earth, and the like. In one
embodiment, silane-reactive filler (b) can be a discrete particle or
group of particles in the form of aggregates and/or agglomerates.
Silane-reactive filler (b) can be mixed with other fillers that do not
react with silane (c). These fillers can be used to either extend rubber
component (a) or to reinforce the elastomeric network.

[0143]Some representative non-limiting examples of suitable
silane-reactive fillers (b) include metal oxides such as silica
(pyrogenic and/or precipitated), titanium dioxide, aluminosilicate,
alumina and siliceous materials such as clays and talc. In one
embodiment, particulate precipitated silica is used in connection with a
silane. Preferably, silane-reactive filler (b) is a silica used alone or
in combination with one or more other fillers. In one embodiment, a
combination of silica and carbon black is utilized for a variety of
rubber products, e.g., treads for tires. Alumina can be used either alone
or in combination with silica. The term "alumina" herein refers to
aluminum oxide, or Al2O3. In a further specific embodiment, the
fillers can be hydrated or anhydrous. Use of alumina in rubber
compositions is known, e.g., from U.S. Pat. No. 5,116,886 and EP 631 982,
the entire contents of both of which are incorporated by reference
herein.

[0144]The term "carrier" as used below shall be understood herein to mean
a porous or high surface area filler or organic polymer that has a high
adsorption or absorption capability and is capable of carrying up to 75
percent liquid silane while maintaining its free-flowing and dry
properties. The carrier filler or carrier polymer herein is essentially
inert to the silane and is capable of releasing or deabsorbing the liquid
silane when added to the elastomeric composition.

[0145]Silane-reactive filler (b) herein can be used as a carrier for
liquid silanes and reinforcing fillers for elastomers in which
halo-functional silane (c) is capable of reacting or bonding with the
surface. The fillers that are used as carriers are non-reactive with
silane (c). The non-reactive nature of the fillers is demonstrated by the
ability of halo-functional silane (c) to be extracted at greater than 50
percent of the loaded silane using an organic solvent. The extraction
procedure is described in U.S. Pat. No. 6,005,027, the entire contents of
which are incorporated herein by reference.

[0146]Representative non-limiting examples of carries include porous
organic polymers, carbon black, diatomaceous earth and silicas that are
characterized by a relatively low differential of less than 1.3 between
the infrared absorbance at 3502 cm-2 of the silica when taken at
105° C. and when taken at 500° C. as described in
aforementioned U.S. Pat. No. 6,005,027. In one embodiment, the amount of
halo-functional silane (c) that can be loaded on the carrier can range
from 0.1 to 70 weight percent. In another embodiment, halo-functional
silane (c) is loaded onto the carrier at concentrations between about 10
and about 50 weight percent.

[0147]Silane-reactive filler (b) includes fillers in which halo-functional
silane (c) is reactive with the surface of the filler. Particulate
precipitated silica is useful as silane-reactive filler (b), especially
when the silica possesses reactive surface silanols. Silane-reactive
filler (b) can be provided in hydrated form.

[0148]Other fillers that can be mixed with silane-reactive filler (b)
include those that are essentially inert to halo-functional silane (c)
with which they are admixed as is the case with carbon black and organic
polymer fillers.

[0149]At least two different silane-reactive fillers can be mixed together
and thereafter reacted with silane(s) (c). Thus, one or more carriers
possessing metal hydroxyl surface functionality such as the silicas and
other siliceous particulates which possess surface silanol functionality
can be mixed with one or more reinforcing fillers containing metal
hydroxyl surface functionality, e.g., alumina, aluminosilicates, clay,
talc, magnesium hydroxide and iron oxide, and thereafter reacted with the
selected silane(s)(c).

[0150]Precipitated silica is advantageously used as silane-reactive filler
(b). Precipitated silica may be characterized as one having a Brunauer,
Emmett and Teller (BET) surface area, as measured using nitrogen gas, in
a range of from 40 to 600, preferably from 50 to 300, and more preferably
from 100 to 150, m2/g. The BET method of measuring surface area is
described in the Journal of the American Chemical Society, Volume 60,
page 304 (1930) and is the method used herein.

[0151]Precipitated silica can also be characterized as one having a
dibutylphthalate (DBP) absorption value in a range of from 100 to 350,
preferably from 150 to 300, and more preferably from 200 to 250.
Silane-reactive fillers (b), as well as the aforesaid alumina and
aluminosilicate fillers, typically have a CTAB surface area in a range of
from 100 to 220 m2/g. The CTAB surface area is the external surface
area as determined by cetyl trimethylammonium bromide with a pH of 9. The
method for the measurement of CTAB surface area is described in ASTM D
3849.

[0152]The surface area of silane-reactive filler (b) can also be expressed
in terms of its mercury porosity surface area as determined by mercury
porosimetry. In this technique, mercury is allowed to penetrate the pores
of a sample of filler after a thermal treatment to remove volatiles. More
specifically, the set-up conditions use a 100 mg sample of filler, remove
volatiles therefrom over 2 hours at 105° C. and ambient
atmospheric pressure and employ a measurement range of from ambient to
2000 bars pressure. Such measurement can be performed according to the
method described in Winslow, et al. in ASTM bulletin, p. 39 (1959) or
according to DIN 66133. For such measurement, a CARLO-ERBA Porosimeter
2000 may be used. The average mercury porosity specific surface area for
the selected silane-reactive filler (b), e.g., silica, will ordinarily be
in a range of from 100 to 300, preferably from 150 to 275, and more
preferably from 200 to 250, m2/g.

[0153]A suitable pore size distribution for silane-reactive filler (b),
e.g., the non-limiting examples of silica, alumina and aluminosilicate,)
according to the aforedescribed mercury porisimetry can be as follows:
five percent or less of its pores have a diameter of less than 10 nm;
from 60 to 90 percent of its pores have a diameter of from 10 to 100 nm;
from 10 to 30 percent of its pores have a diameter of from 100 to 1,000
nm; and from 5 to 20 percent of its pores have a diameter of greater than
1,000 mm Silane-reactive filler (b), e.g., silica, can be expected to
have an average ultimate particle size, e.g., in the range of from 0.01
to 0.05 μm as determined by electron microscopy, although the
particles can be even smaller, or possibly larger, in size. Various
commercially available silicas can used herein such as those available
from PPG Industries under the HI-SIL trademark, in particular, HI-SIL 210
and 243; silicas available from Rhone-Poulenc, e.g., ZEOSIL 1165 MP;
silicas available from Degussa, e.g., VN2 and VN3, etc., and silicas
available from Huber, e.g., HUBERSIL 8745.

[0154]Where it is desired for a rubber composition containing both a
siliceous filler such as silica, alumina and/or aluminosilicate and a
carbon black reinforcing pigment, to be primarily reinforced by the
siliceous filler, the weight ratio of siliceous filler to carbon black
can be up to 30/1 and, advantageously, is within the range of from 3/1 to
10/1.

[0155]Silane-reactive filler (b) can comprise from 15 to 95 weight percent
precipitated silica, alumina and/or aluminosilicate and, correspondingly,
from 5 to 85 weight percent carbon black having a CTAB value in a range
of from 80 to 150. Alternatively, silane-reactive filler (b) can comprise
from 60 to 95 weight percent of said silica, alumina and/or
aluminosilicate and, correspondingly, from 40 to 5 weight percent of
carbon black. The siliceous filler and carbon black, when used together,
can be pre-blended or blended together in the manufacture of the
vulcanized rubber.

[0156]In still another embodiment, there is provided herein a process for
preparing a rubber composition comprising mixing components (a), (b), (c)
and optionally, (d), in effective amounts. An effective amount of
halo-functional silane (c) can range from 0.2 to 20, preferably from 0.5
to 15, and more preferably from 2 to 10, weight percent based on the
total weight of the rubber composition. An effective amount of
silane-reactive filler (b) can range from 2 to 70, preferably from 5 to
50, and more preferably from 20 to 40, weight percent based on the total
weight of the rubber composition. An effective amount of rubber component
(a) can range from 30 to 90, preferably from 50 to 95, and more
preferably from 60 to 80, weight percent based on the total weight of the
rubber composition. The process for preparing the rubber composition can
further comprise curing the composition, before, during and/or after its
molding. A vulcanized rubber composition should contain a sufficient
amount of silane-reactive filler (b) to achieve a reasonably high modulus
and high resistance to tear. Specifically, an effective amount of
silane-reactive filler (b) can be as low as 5 to 100 parts per hundred
parts of rubber (phr) component (a), and preferably from 25 to 85, and
more preferably from 50 to 70, phr.

[0157]Halo-functional silane (c) can be premixed, or pre-reacted, with
particles, aggregates and/or agglomerates of silane-reactive filler (b)
or it can be added to the rubber mix during the processing or mixing of
rubber (a) and silane-reactive filler (b). If halo-functional silane (c)
and silane-reactive filler (b) are added separately to the process
mixture during the mixing of rubber component (a) and silane-reactive
filler (b), silane (c) can be considered to have coupled in situ to
silane-reactive filler (b).

[0158]In practice, sulfur-vulcanized rubber products typically are
prepared by thermomechanically mixing rubber and various ingredients in a
sequentially step-wise manner followed by shaping and curing the
compounded rubber to form a vulcanized product. More specifically, first,
for the aforesaid mixing of rubber component(s)(a) and various
ingredients, typically exclusive of sulfur and sulfur vulcanization
accelerators (collectively "curing agents"), the rubber(s) and various
rubber compounding ingredients are usually blended in at least one, and
optionally two or more, preparatory thermomechanical mixing stage(s) in
suitable mixers. Such preparatory mixing is referred to as non-productive
mixing or as non-productive mixing steps or stages. Such preparatory
mixing is typically conducted at temperatures in the range of from
130° C. to 180° C. and preferably from 140° C. to
160° C.

[0159]Subsequent to the preparatory mixing stage, in a final mixing stage,
which may also be referred to as a productive mixing stage, curing
agents, and, optionally, one or more additional ingredients, are mixed
with the rubber compound or composition, typically at a temperature in
the range of from 50° C. to 130° C., which is a lower
temperature than that utilized in the preparatory mixing stage, in order
to prevent or retard premature curing (i.e., "scorching") of the
sulfur-curable rubber.

[0160]The rubber composition typically is allowed to cool, sometimes after
or during a process of intermediate mill mixing, between the aforesaid
mixing steps, e.g., to a temperature of 50° C. or lower.

[0161]When it is desired to mold and cure the rubber composition, the
rubber composition is placed in the desired mold and heated to at least
130° C. and up to 200° C. to bring about the vulcanization
of the rubber.

[0162]By thermomechanical mixing is meant that the rubber compound, or
composition of rubber and rubber compounding ingredients, is mixed in a
rubber mixer under high shear conditions where by it autogenously heats
up, primarily due to shear and associated friction.

[0163]Several chemical reactions can occur at various steps in the mixing
and curing processes. For example, the independent addition of a sulfur
source can be manipulated by the amount of addition thereof and by
sequence of addition relative to the addition of other ingredients to the
rubber mixture.

[0164]The rubber composition of the invention is advantageously prepared
by the process which comprises:

[0172]In preferred embodiments of the foregoing two-stage process:
preparatory mixing step (A) is carried out at a temperature of from
140° C. to 180° C. for from 1 to 20 minutes, and preferably
at a temperature of from 150° C. to 170° C. for from 4 to
15 minutes, with 100 parts by weight of sulfur-vulcanizable rubber
component (a) selected from the group consisting of conjugated diene
homopolymers and copolymers of at least one conjugated diene and aromatic
vinyl compound, from 5 to 100, and preferably from 25 to 80, parts by
weight of silane-reactive filler (b) containing from 0 to 85 weight
percent carbon black, from 0.05 to 20, and preferably, from 2 to 10,
parts by weight of halo-functional silane (c) and, optionally, from 0.01
to 15, and preferably from 1 to 5, parts by weight of activating agent
(d); final mixing step (B) is carried out with from 0 to 5 parts by
weight of at least one curing agent at a temperature of from 50°
C. to 130° C. for from 1 to 30, and preferably from 1 to 5,
minutes; and, optional curing step (C) is carried out at a temperature of
from 130° C. to 200° C. for a period of from 5 to 600, and
preferably 10 to 60 minutes.

[0173]The rubber composition herein can be compounded by methods known in
the rubber compounding art such as mixing component (a) (the various
sulfur-vulcanizable constituent rubbers) with various commonly used
additive materials such as, for example, curing aids such as sulfur,
activators, retarders and accelerators, processing additives such as
oils, resins, e.g., tackifying resins, silicas, plasticizers, fillers,
pigments, fatty acid, zinc oxide, waxes, antioxidants and antiozonants,
peptizing agents, and reinforcing materials such as, e.g., carbon black,
and the like. Depending on the intended use of the rubber composition
(sulfur-vulcanizable) and cured rubber composition (sulfur-vulcanized
material), the aforementioned additives may be selected and used in known
and conventional amounts.

[0174]Vulcanization can be conducted in the presence of an additional
sulfur vulcanizing agent. In one embodiment, some illustrative
non-limiting examples of suitable sulfur vulcanizing agents include,
e.g., elemental sulfur (free sulfur) or sulfur-donating vulcanizing
agents such as amino disulfide, polymeric polysulfide or sulfur-olefin
adducts which are conventionally added in the final, i.e., productive,
rubber composition mixing step. In another specific embodiment, the
sulfur vulcanizing agents (which are common in the art) are used, or
added, in the productive mixing stage, in an amount ranging from up to
about 8 phr, with a range preferably of from 0.4 to 5 phr, and more
preferably of from about 1.5 to about 4.0 phr, and in some cases from
about 2 to about 2.5 phr, being generally suitable.

[0176]Accelerators can be added to control the time and/or temperature
required for vulcanization and to improve the properties of the
vulcanizate. A single accelerator system can be used, i.e., a primary
accelerator. Conventionally primary accelerator(s) can be used in amounts
ranging from 0.5 to 4, and preferably from 0.8 to 1.5 phr. Combinations
of a primary and a secondary accelerator can be used with the secondary
accelerator being used in smaller amounts, e.g., from 0.05 to 3 phr, in
order to activate and to improve the properties of the vulcanizate.
Delayed action accelerators and/or vulcanization retarders can also be
used.

[0177]Suitable types of accelerators include amines, disulfides,
guanidines, thioureas, thiazoles, thiurams, sulfenamides,
dithiocarbamates, xanthates and combinations thereof. The primary
accelerator can be a sulfenamide. If a second accelerator is used, it can
be a guanidine, dithiocarbamate or thiuram compound.

[0178]Optional tackifier resins can be used at levels of from 0.5 to 10
phr, and preferably from 1 to 5, phr. Typical amounts of processing aids
range from 1 to 50 phr. Suitable processing aids can include aromatic,
naphthenic and/or paraffinic processing oils and combinations thereof.
Typical amounts of antioxidants are from 1 to 5 phr. Representative
antioxidants include diphenyl-p-phenylenediamine and others, e.g., those
disclosed in the Vanderbilt Rubber Handbook (1978), pages 344-346.
Typical amounts of antiozonants are from 1 to 5 phr. Typical amounts of
optional fatty acids, e.g., stearic acid, are from 0.5 to 3 phr. Typical
amounts of zinc oxide are from 2 to 5 phr. Typical amounts of waxes,
e.g., microcrystalline wax, are from 1 to 5 phr. Typical amounts of
peptizers, e.g., pentachlorothiophenol, dibenzamidodiphenyl disulfide and
combinations thereof, are from 0.1 to 1 phr.

[0179]The rubber composition herein can be used for any of a variety of
purposes. In one specific embodiment herein, there is provided an article
of which at least one component is the herein-described cured rubber
composition. In another specific embodiment herein, there is provided a
tire at least one component of which, e.g., its tread, comprises the
herein-described cured rubber composition. In yet another specific
embodiment, the rubber composition herein can be used for the manufacture
of such articles as shoe soles, hoses, seals, cable jackets, gaskets or
other industrial goods. Such articles can be built, shaped, molded and
cured by various known and conventional methods as is readily apparent to
those skilled in the art.

[0180]The invention can be better understood by reference to the following
examples in which the parts and percentages are by weight unless
otherwise indicated.

COMPARATIVE EXAMPLE 1

Preparation of 3-chloropropenyltriethoxysilane (Silane A)

[0181]A 250 ml 3-neck round-bottom flask was equipped with a reflux
condenser, addition funnel and stir bar. Propargyl chloride (50 g, 0.671
mol) and 0.15 g of platinum
(±)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (3% by wt. in
xylenes) were added to the flask. Triethoxysilane (115.6 g, 0.705 mol)
was added dropwise from the addition funnel to the reaction mixture. The
flask quickly became warm. After the completion of addition, the flask
was kept at 100° C. for one hour. The final product 103 g was
purified by distillation (108° C./49 mmHg) as a mixture of
isomers. NMR showed a ratio of 1:0.13 of the two isomers.

COMPARATIVE EXAMPLE 2

Preparation of (p-chloromethylphenylethyl)triethoxysilane (Silane B)

[0182]A 2-liter 3-neck round-bottom flask was equipped with a reflux
condenser, addition funnel and stir bar. Vinylbenzyl chloride (458 g, 3.0
mol), platinum-tetravinyl tetramethyl-cyclotetrasiloxane complex (0.15 g,
50 ppm Pt) as catalyst, and phenothiazine (0.86 g, 0.1% by wt.) as a
promoter were added to the flask. After heating the flask to 70°
C., trichlorosilane (406.2 g, 3.0 mol) was added dropwise from the
addition funnel to the reaction mixture. After the completion of
addition, the flask was kept at around 80° C. for 3 hours. After
distillation, the expected hydrosilation product
(p-chloromethylphenylethyl)trichlorosilane was obtained and then
transesterified with ethanol to produce
(p-chloromethylphenylethyl)triethoxysilane (92% yield) as Silane B.

[0183]A 1 liter round bottom flask fitted with magnetic stirrer, addition
funnel, distillation head, 2 thermocouples, receiver and dry ice trap was
charged with 100 grams (0.36 moles) of
1-chloromethyl-4-(2-trimethoxysilylethyl)benzene along with 0.099 grams
(0.00052 moles) p-toluenesulfonic acid monohydrate. Into the addition
funnel was charged 98.3 grams (1.09 moles) 2-methyl-1,3-propanediol. A
vacuum pump was connected and the vacuum was lowered while the reaction
pot was heated gently (86° C.). To this mixture was added
2-methyl-1,3-propanediol. The mixture was heated for 3 hours 15 minutes
and the methanol that was formed during the reaction was removed under
reduced pressure resulting in a clear liquid product as silane A. GPC
showed the product has a number average molecular weight as 700 (or 800
for weight average molecular weight).

[0186]In the following examples, the amounts of reactants are parts per
hundred of rubber (phr) unless otherwise indicated. The following rubber
compositions were prepared based on natural rubber and reinforced with
highly dispersible precipitated silica, the said compositions being
intended for tread compounds in truck tires. Formulations for the rubber
compositions of these examples are described below in Table 1. The rubber
composition of Comp(arative) Ex(ample) 3 contains carbon black as the
reinforcing filler. The remaining rubber compositions (Comp. Exs. 4 and 5
and Exs. 4 and 5) contain silica as the reinforcing filler. The silane
coupling agents tested are used in equal molar amounts of silicon. The
rubber compositions of Comp. Ex. 4 and Exs. 4 and 5 have the same
formulations except for the silane component.

[0188]The mixing of the rubber masterbatch was done in a two-pass
procedure as hereinafter described using a Krupp mixer with a 1550 cubic
centimenter (cc) chamber volume. In the first pass, the mixer was turned
on with the mixer at 30 rpm and the cooling water on full. The rubber
polymers were added to the mixer and ram down mixed for 60 seconds. Half
of the silica and all of the silane with approximately 35-40 grams of
this portion of silica in an ethylvinyl acetate (EVA) bag were added and
ran down mixed for 60 seconds. The remaining silica and the processing
oil in an EVA bag were next added and ram down mixed for 60 seconds. The
mixer throat was dusted down, and the mixer's mixing speed was increased
to 90 rpm as required to raise the temperature of the rubber masterbatch
to 140° C. The master batch was dumped (removed from the mixer), a
sheet was formed on a roll mill set at about 60° to 65° C.
and the sheet allowed to cool to ambient temperature.

[0189]In the second pass, the sheets from the first pass were added to the
mixer and ram down mixed for 60 seconds. The rest of the ingredients
except for the curatives were added together and ram down mixed for 60
seconds. The mixer throat was dusted down and the mixer's mixing speed
was increased to 90 rpm as required to raise the temperature of the
rubber master batch to between 135° C. to 140° C. The
rubber master batch was mixed for five minutes and the speed of the Krupp
mixer as adjusted to maintain the temperature between 135° C. and
140° C.

[0190]The rubber masterbatch and the curatives were mixed on a roll mill
heated to between 60° C. and 65° C. The sulfur and
accelerators were added to the rubber masterbatch and thoroughly mixed on
the roll mill and allowed to form a sheet. The sheet was cooled to
ambient before curing.

[0191]The measurements and tests used to characterize the rubber
compositions are described below. The rubber compositions are
characterized before and after curing, as indicated below.

[0192]The rheological properties of the compositions were measured on a
Monsanto R-100 Oscillating Disk Rheometer and a Monsanto M1400 Mooney
Viscometer. The specimens for measuring the mechanical properties were
cut from 6 mm plaques cured for (t90+1) minutes at 149° C. Curing
and testing of the cured rubber compositions in the form of plaques were
carried out according to ASTM standards. In addition, small strain
dynamic tests were carried out on a Rheometrics Dynamic Analyzer
(ARES-Rheometrics Inc.). Payne effect strain sweeps were carried out from
dynamic strain amplitudes of 0.01% to about 25% shear strain amplitude at
10 Hz and 60° C. The dynamic parameters, G'initial,
ΔG', G''max and tan δmax, were extracted from the
non-linear responses of the rubber compounds at small strains. In some
cases, steady state values of tan δ were measured after 15 minutes
of dynamic oscillations at strain amplitudes of 35% (at 60° C.).
Temperature dependence of dynamic properties was also measured from about
-80° C. to +80° C. at small strain amplitudes (1 or 2%) at
a frequency of 10 Hz.

[0193]The specific curing procedure and measuring procedures were as
follows:

[0195]These experimental tests demonstrate the improved (filler/polymer)
coupling performances in the rubber compositions of the present invention
compared with known rubber compositions such as those using a carbon
black filler (Comp. Ex. 3) or a conventional silane coupling agent such
as A-1289 (Comp. Ex. 4).

[0196]The data for various properties measured before and after curing of
the rubber formulations of Table 1 are presented in Tables 2, 3, and 4
below.

[0197]The advantage for reinforcement power obtained with silane (c) in
accordance with the invention herein will be readily apparent to those
skilled in the art.

[0198]Examination of the data presented in Tables 2, 3 and 4 leads to the
following observations: the Mooney viscosity values are all low,
indicating the good ability of the compositions to be processed in the
uncured state and scorching times are long enough to provide a good
safety margin.

[0199]Compared with the compositions of Comp. Exs. 3 and 4 (the control
compositions for carbon black and Silquest A-1289 silane, respectively),
those of Ex. 5 have significantly better overall characteristics. In
particular, the modulus value under higher deformation (M300) and the
(M300/M100) ratio are both appreciably higher for Ex. 5 than for Comp.
Exs. 3 and 4 indicating better reinforcement for the former compared with
the latter.

[0200]The rubber composition of this invention is particularly
advantageous for use in the manufacture of tire treads exhibiting low
rolling resistance and high wear resistance, especially when the treads
are based on natural rubber or synthetic polyisoprene.

[0201]While the invention has been described with reference to a number of
exemplary embodiments, it will be understood by those skilled in the art
that various changes can be made and equivalents can be substituted for
elements thereof without departing from the scope of the invention. In
addition, many modifications can be made to adapt a particular situation
or material to the teachings of the invention without departing from
essential scope thereof. Therefore, it is intended that the invention not
be limited to any particular exemplary embodiment disclosed herein.